1. Technical Field
The present invention relates to a circuit device, a physical-quantity detecting apparatus, an electronic apparatus, a moving object, and the like.
2. Related Art
There has been known a circuit device that detects a physical quantity on the basis of a detection signal from a physical quantity transducer. Taking a gyro sensor as an example, the circuit device detects angular velocity and the like as physical quantities. The gyro sensor is incorporated in electronic apparatuses such as a digital camera and a smart phone and moving objects such as a car and an airplane. Camera shake correction, posture control, GPS autonomous navigation, and the like are performed using detected physical quantities such as angular velocity.
As the circuit device of such a gyro sensor, for example, there is a technique disclosed in JP-A-2008-122122.
In JP-A-2008-122122, a differential-signal processing circuit such as a differential amplifier circuit or a gain adjustment amplifier is provided at a post stage of first and second Q/V conversion circuits (charge/voltage conversion circuits) of a detection circuit. The differential-signal processing circuit amplifies a differential component between first and second signals from the first and second Q/V conversion circuits and outputs the differential component to a circuit at a post stage.
However, in the past, failure detection of the differential-signal processing circuit cannot be performed. For example, although failure detection of the entire detection circuit is possible, a failure of the differential-signal processing circuit cannot be individually detected. For example, when a differential component is seen as being normally differentially amplified, although the differential-signal processing circuit is actually out of order, proper failure detection of the differential-signal processing circuit cannot be realized by the failure detection of the entire detection circuit. Therefore, when a failure occurs over time in the differential-signal processing circuit while the circuit device is actually operating, appropriate measures cannot be taken against the failure. As a result, for example, deterioration in reliability occurs.